In this video, Dr. Michio Kaku, a theoretical physicist and bestselling author, reveals possible causes for déjà vu—the strange feeling that you’ve experienced a situation before, when you know you haven’t.

One theory that tries to explain this phenomenon is that you may have actually already experienced a similar situation before. Being in this familiar situation “elicits fragments of memories that we have stored in our brain,” says Dr. Kaku.

This theory has been experimentally proven and “explains most [cases of] déjà vu,” added Dr. Kaku.

However, quantum physics states that there is the possibility that déjà vu might be caused by your ability to “flip between different universes,” says Dr. Kaku.

Dr. Kaku brings up an analogy Steve Weinberg, the famous theoretical physicist and Nobel Prize winner, gave of how the concept of a multiverse in quantum physics is very much alike to the concept of radio waves.

Similar to how radio waves of various frequencies exist in your living room, there are multiple universes existing in tandem. While your radio is tuned to pick up a certain frequency and thus a single radio station, our universe consists of atoms that are oscillating at a unique frequency that other universes are not vibrating at.

Universes are usually not “in phase”, that is vibrating at the same frequency, with each other due to the divisions caused by time, but when they are “in phase” it is theoretically possible to “move back and forth” between universes.

So although it is “uncertain”, it could be possible that when you are experiencing déjà vu, you are “vibrating in unison” with a parallel universe, explains Dr. Kaku